Hot glycol plasticizing removal of halogenated hydrocarbon solvent scouring liquor on polyester textiles

ABSTRACT

Polyester-containing textile materials are scoured with an organic solvent and the solvent is removed by passing the scoured textile into a liquid maintained at elevated temperatures. The liquid is a substantially anhydrous, inert organic liquid which is a swelling agent for the polyester fibers of the textile material. The swelling agent allows an effective incorporation of a finishing material, such as a dye, into the textile material.

United States Patent Inventor Harold Pirie Runcorn, England Appl. No. 755,741 Filed Aug. 27, 1968 Patented Nov. 2, 1971 Assignee Imperial Chemical Industries Limited London, England Priority Sept. 6, 1967 Great Britain 40,758/67 HOT GLYCOL PLASTICIZING REMOVAL OF HALOGENATED HYDROCARBON SOLVENT SCOURING LIQUOR ON POLYESTER TEXTILES 5 Claims, No Drawings 11.8. CI 8/l30.l, 8/17, 8/19, 8/142, 8/175 Int. Cl D06m Field of Search 8/19, 174, 166,173,142,l75

References Cited UNITED STATES PATENTS 2/1942 Whitehead 8/173 White, American Dyestuff Reporter 7/31/67 pages P591- P597.

Primary Examiner-Donald Levy Attorney-Cushman, Darby & Cushman ABSTRACT: Polyester-containing textile materials are scoured with an organic solvent and the solvent is removed by passing the scoured textile into a liquid maintained at elevated temperatures. The liquid is a substantially anhydrous, inert organic liquid which is a swelling agent for the polyester fibers of the textile material. The swelling agent allows an effective incorporation of a finishing material, such as a dye, into the textile material.

HOT GLYCOL PLASTICIZING REMOVAL OF IIALOGENATEI) IIYDROCARBON SOLVENT SCOURING LIQUOR N POLYESTER TEXTILES This invention relates to a treatment of textile materials to render them suitable for subsequent processing. In particular the invention relates to a process for treating textile materials, notably polyester fiber materials, to render them susceptible to dyeing and other finishing processes and to such processes which include a dyeing or other finishing operation.

It is well known to treat textile materials with chemicals to remove fats, waxes, grease and other impurities therefrom to render the fibers susceptible to dyeing and other finishing processes, such treatments being commonly termed scouring treatments. A known scouring process, which is commonly termed a solvent scouring process, involves treating the materials with a boiling organic liquid, for example a chlorinated aliphatic hydrocarbon, which is a solvent for fats, waxes and grease. This solvent scouring treatment is usually followed by rinsing in boiling, substantially pure solvent and finally by removal of the solvent, for example by passing the solvent-laden material into hot water or steam to cause evaporation of the solvent. Removal of the solvent by rapid vaporization in this way is commonly termed an aqueous flashoff treatment.

The textile materials resulting from the above treatment in general have satisfactory properties rendering them suitable for dyeing and other finishing processes, and if desired finishing processes may follow the solvent removal treatment directly. For example we have described a process for finishing textile materials, including a scouring step, in copending application No. 21906/65, this process comprising scouring the textile material with an organic solvent, removing the solvent from the textile material in an aqueous flash-off stage, and applying a dyestuff or finishing agent to the textile material in the aqueous flash-off stage.

While this finishing process, and also finishing process applied subsequent to the solvent removal stage, are satisfactory for treating the majority of textile fibers, there are special types of fibers, notably polyester fibers, which cannot be dyed satisfactorily from a solution or dispersion of dyestuff unless the fiber structure is modified in some way to enable penetration thereof by the dyestuff molecules.

A known process for rendering polyester materials susceptible to dyeing is described in US. Pat specification No. 2,938,811 and comprises immersing the material in an anhydrous, relatively high-boiling, water-soluble, inert organic liquid at an elevated temperature of at least 250 X F. (i.e. 121 X C.), and immediately contacting the material with relatively cool water to remove surplus organic liquid from the surface of the fibers. This treatment leaves a small amount of the organic liquid entrapped within the fiber structure, so modifying the fiber structure to enable penetration thereof by the dyestuff molecules.

We have now found that polyester and other textile materials can be rendered susceptible to dyeing and other finishing processes. and in fact can be dyed or otherwise finished, in a continuous process involving a scouring stage and, in the case of polyester fibers, a structure-modifying stage.

According to the present invention we provide a continuous process for the treatment of textile materials which comprises treating the textile material with an organic solvent to scour the material, and passing the resulting solvent-laden textile material directly into a substantially anhydrous, inert organic liquid at an elevated temperature sufficient to cause evaporation of the solvent.

The process is particularly adaptable for use in dyeing textile materials. In this case the material, after passage through the hot, anhydrous, inert liquid, may be treated with a dyestuff, if desired after an intermediate treatment with water to remove surplus organic liquid from the surface of the material. Alternatively a dyestuff may be incorporated in the hot inert liquid so that evaporation of the solvent and dyeing occur simultaneously. In the latter case the dyeing stage may be followed by a treatment in cool water to remove surplus dyestuff and organic liquid from the surface of the material. The dyeing stage can then be completed by removing the organic liquid. If a prolonged dyeing time is required, the textile material impregnated with swelling agent and dyestuff can be rolled and stored for the desired period of time. The process may be adapted for the application of any finishing agent to the textile material instead of the dyestuff or in addition to it.

The process of the invention is especially useful for finishing and particularly for dyeing polyester fibers since by suitable choice of the inert liquid used to cause evaporation of the solvent, modification of the fiber structure and finishing can take place simultaneously. However, the process may equally well be employed for treating any textile materials which will withstand the elevated temperatures involved.

Where dyeing or other finishing is to be carried out in the solvent removal stage, the dyestuff can be soluble in the hot, inert organic liquid so that it is present in solution in the liquid, or it may be insoluble in which case it may be present as a dispersion in the liquid. In the preferred use of the process for treating polyester fiber materials the dyestuff can conveniently be of the type known as disperse dyestuffs. The amount of the dyestuff or other finishing agent in the liquid can be the same as is normally employed in finishing treatments for the particular textile material to be treated.

The inert organic liquid into which the solvent-laden textile material is passed to cause evaporation of the solvent should have a relatively high boiling point so that it remains in the liquid phase at the temperature of the treatment. This temperature will usually be in excess of the boiling point of the scouring solvent so that rapid evaporation, or flash-off," is achieved. Usually the liquid will have a boiling point in excess of C. and those of boiling point C. or greater are preferred. In addition we have found that the liquid is preferably soluble in water so that surplus liquid can be removed easily from the surface of the fiber by rinsing with cool water, and also it is with advantage substantially nonvaporizable at the temperature of use. Examples of suitable organic liquids are polyhydroxy compounds and polyalkylene glycols, particularly the dialkylene glycols, diethylene glycol and dipropylene glyol.

The temperature of the organic inert liquid during the treatment depends both upon the organic solvent used in the scouring stage and upon the degree of modification of fiber structure (if appropriate) required. The temperature will usually be such that rapid evaporation (or flashing off'j of the scouring solvent is ensured and can be such that the desired degree of modification of fiber structure is achieved. For example if diethylene glycol is used to cause evaporation of the scouring solvent, temperatures of at least 120 C. may be required to achieve a rapid modification 0f the fiber structure of polyester fiber materials. In some cases, however, it may not be desired to apply dyestuff to the textile material directly after the solvent evaporation stage. In this case a lower temperature may be employed in the solvent removal stage, but which is still high enough to cause evaporation of the solvent, and the textile material can then be rolled and stored while impregnated with the liquid to allow structure modification (if appropriate) to take place.

Since it is desirable to recover the vaporized scouring solvent for reuse, the solvent removal vessel will usually be closed and will contain provision for condensing the vapors and returning the condensate to the scouring vessel; if desired means may be included for separating the solvent from any other condensate which may be obtained.

The scouring solvent can be any of the organic solvents or mixtures of solvents usually employed in solvent-scouring processes; in particular it can be a halogenated hydrocarbon solvent, for example a chlorinated aliphatic hydrocarbon solvent, and especially trichloroethylene or perchloroethylene. Sensitive textile materials can be scoured using a mild halogenated hydrocarbon solvent, for example trichlorotrifiuoroethane.

Whatl claim is:

2. A process as claimed in claim 1 wherein the textile material is subsequently washed with water to remove surplus inert organic liquid from the surface of the fibers.

3. A process as claimed in claim 1 wherein the polyalkylene glycol is diethylene glycol.

4. A process as claimed in claim 1 wherein the solvent is a chlorinated aliphatic hydrocarbon.

5. A process as claimed in claim 4 wherein the solvent is trichloroethylene. 

2. A process as claimed in claim 1 wherein the textile material is subsequently washed with water to remove surplus inert organic liquid from the surface of the fibers.
 3. A process as claimed in claim 1 wherein the polyalkylene glycol is diethylene glycol.
 4. A process as claimed in claim 1 wherein the solvent is a chlorinated aliphatic hydrocarbon.
 5. A process as claimed in claim 4 wherein the solvent is trichloroethylene. 